Computing devices, such as notebook computers, personal digital assistants, mobile communication devices, portable entertainment devices (e.g., handheld video game devices, multimedia players), and set-top-boxes (e.g., digital cable boxes, digital video disc (DVD) players) may include user interface devices that facilitate interaction between a user and the computing device.
One type of user interface device that has become more common operates by way of capacitance sensing. A capacitance sensing system may include a touchscreen, touch-sensor pad, a touch-sensor slider, or touch-sensor buttons, and may include an array of one or more capacitive sensor elements. Capacitive sensing typically involves measuring a change in capacitance associated with the capacitive sensor elements to determine a presence conductive object relative to the capacitive sensor elements. The measured changes in capacitance may be used to calculate a centroid that indicates position of the conductive object. The conductive object may be, for example, a stylus or a user's finger.
Noise signals from various sources may affect accuracy and consistency in detecting a presence of a conductive object. When a detected presence is used to determine further information about a conductive object, such as the position of a conductive object, the noise may also affect the accuracy and consistency of that further information.